Results 1 to 10 of about 62,625 (286)

X-ray active galactic nuclei in the core of the Perseus cluster [PDF]

Monthly Notices of the Royal Astronomical Society, 2007
We present a study of the X-ray emission from the nuclei of galaxies observed in the core of the Perseus cluster in a deep exposure with Chandra. Point sources are found coincident with the nuclei of 13 early-type galaxies, as well as the central galaxy NGC1275. This corresponds to all galaxies brighter than M_B = -18 in the Chandra field. All of these
S. Santra, Andrew C. Fabian, Jeremy S. Sanders   +2 more
semanticscholar   +7 more sources

X-ray Eclipses of Active Galactic Nuclei [PDF]

The Astrophysical Journal, 2017
X-ray variation is a ubiquitous feature of active galactic nuclei (AGNs), however, its origin is not well understood. In this paper, we show that the X-ray flux variations in some AGNs, and correspondingly the power spectral densities (PSDs) of the ...
Lu, Youjun, Yu, Qingjuan, Zhang, Fupeng
core   +4 more sources

Soft X-ray active galactic nuclei

The Astrophysical Journal, 1984
The discovery of 10 active galactic nuclei (AGNs) based upon optical observations of Einstein Observatory X-ray sources is reported. The new objects are optically similar to AGNs that have been identified by others with this technique. One notable exception, the quasar E1821 + 643, is associated with a previously unidentified X-ray source detected with
F. E. Marshall, S. H. Pravdo
openaire   +3 more sources

Review on Active Galactic Nuclei at hard X-ray energies [PDF]

Proceedings of An INTEGRAL view of the high-energy sky (the first 10 years) - 9th INTEGRAL Workshop and celebration of the 10th anniversary of the launch — PoS(INTEGRAL 2012), 2013
Hard X-ray surveys are an important tool for the study of active galactic nuclei (AGN): they provide almost an unbiased view of absorption in the extragalactic population, allow the study of spectral features such as reflection and high energy cut-off ...
Bassani, Loredana, Bazzano, A., Bird, A. J., Landi, R., Malizia, A., Molina, M., Panessa, F., Stephen, J. B., Ubertini, P.   +8 more
core   +2 more sources

The Infrared-X-ray continuum correlation in Active Galactic Nuclei [PDF]

Monthly Notices of the Royal Astronomical Society, 2003
The correlation between the soft X-ray and near infrared emission from AGN is analysed using composite models by the code SUMA. We find new evidences for differences in ranges of parameters which characterize the NLR of Seyfert galaxies and LINERs ...
Campos, P. E., Contini, M., Viegas, S. M.   +2 more
core   +4 more sources

X-ray bolometric corrections for Compton-thick active galactic nuclei [PDF]

, 2017
We present X-ray bolometric correction factors, $\kappa_{Bol}$ ($\equiv L_{Bol}/L_X$), for Compton-thick (CT) active galactic nuclei (AGN) with the aim of testing AGN torus models, probing orientation effects, and estimating the bolometric output of the ...
Ballantyne, D. R., Baloković, M., Bauer, F. E., Boorman, P., Brandt, W. N., Brightman, M., Buchner, J., Comastri, A., Del Moro, A., Farrah, D., Gandhi, P., Harrison, F. A., Koss, M., Lanz, L., Masini, A., Ricci, C., Stern, D., Vasudevan, R., Walton, D. J.   +18 more
core   +6 more sources

Variability and the X-ray/UV ratio of Active Galactic Nuclei [PDF]

Astronomy and Astrophysics, 2010
The observed relation between the X-ray radiation from AGNs, originating in the corona, and the optical/UV radiation from the disk is usually described by the anticorrelation between the UV to X-ray slope alpha_ox and the UV luminosity.
Antonucci, M., Trevese, D., Turriziani, S., Vagnetti, F.   +3 more
core   +7 more sources

X-ray power law spectra in active galactic nuclei [PDF]

Astronomy and Astrophysics, 2010
X-ray spectra of active galactic nuclei (AGN) are usually described as power law spectra, characterized by the spectral slope $\alpha$ or photon index $\Gamma$. Here we discuss the X-ray spectral properties within the framework of clumpy accretion flows,
Courvoisier, Deluit, Ishibashi, Ishibashi, Kelly, Laor, McHardy, McLure, Middleton, Nandra, Niko▯ajuk, Page, Papadakis, Papadakis, Piconcelli, Porquet, Reeves, Risaliti, Shemmer, Shemmer, Soldi, T. J.-L. Courvoisier, Titarchuk, Titarchuk, W. Ishibashi, Zdziarski, Zdziarski, Zdziarski   +27 more
core   +4 more sources

Ultraviolet and X-ray variability of active galactic nuclei withSwift [PDF]

Monthly Notices of the Royal Astronomical Society, 2016
14 pages, 8 figures, 4 tables in main text, plus 15 pages of figures in appendices.
D. J. K. Buisson, A. M. Lohfink, W. N. Alston, A. C. Fabian   +3 more
openaire   +5 more sources

Host galaxy properties of X-ray active galactic nuclei in the local Universe [PDF]

Astronomy & Astrophysics, 2021
We study the host galaxy properties of active galactic nuclei (AGN) that have been detected in X-rays in the nearby Universe ( z < 0 . 2). For that purpose, we use the catalogue provided by the ROSAT-2RXS in the 0.1–2.4keV energy band, one of the largest
L. Koutoulidis, G. Mountrichas, I. Georgantopoulos, E. Pouliasis, M. Plionis   +4 more
semanticscholar   +1 more source